Related to the above issue with brakes, looking some more into in-hub gubbins raised the option of an internal gear and brake solution. It would certainly be tidy and low maintenance, would allow a single chainring and sprocket so hugely reduce the likelihood of the chain parting company.

Shimano Nexus stuff looks OK, reasonably priced but perhaps a bit weighty and not exactly pretty. I guess a roller brake might be better to handle than a coaster brake which sort of limits options, and I'd be looking for a good range of gears, 7 or 8 speed seem common enough. The higher spec Alfine stuff looks to be all disc brake rather than internal so not much use really since the whole point is an alternative to discs brakes. Offerings from Sturmney Archer, SRAM etc are all there too. I’ll need to ‘weigh up’ the comparison to normal components. Any advice welcome!

Two early issues for me really. First that I would have to buy stuff, I already have normal gears and brakes in the spares bin so any new kit would add to the build cost. Second is I have zero experience of operating, servicing or maintaining such systems so don’t really know what I would be letting myself in for.

yeah thats a bit much for my piggy bank right now. If I can use my existing disc brakes and normal gears then thats fine and cost is minimised. I do like the idea of this. I was looking more at the 8 speed (RD8) but that's more like £150-170, plus the shifter and sprocket like you say. I guess the range will be similar just with fewer increments.

Forget levers/shifters and cables for now, chain too. Let’s assume whatever I do I will have those. Lets look at a rear wheels worth of brakes and gears, taking XT 750/755 9sp as a benchmark:V brake arms ~220gRear mech ~245gCassette ~260gHub ~400g

That’s ~1.1kg for good old fashioned v brakes and derailleur gears.

But I would be looking for the disc brake setup, and the equivalent disc hub comes in at more like 500g, and lets take the hope mono mini as a benchmark (coz I have some in the shed) its listed at ~400g (although BB7 would come in at closer to 350g) and the external gear plus disc brake setup weighs in at (brake @ 400g + hub @ 500g + cassette @ 260g + mech @ 245g) around 1.4kg.

Compare that to a Nexus 7sp (~£150) in-hub setup all of that gubbins is in one hub with the gears inside and a roller brake bolted to the side, listed at 1.5-1.6kg depending where you look. That’s only a ~200g difference.

The sturmney archer RD8 (~£180) with 8 internal gears and drum brake is listed at 2.2kg and the RD5 (£125) with 5 gears a whopping 2.2 or 2.4kg depending whether you go for the bigger brake. That's at least another half a kilo to consider there compared to the shimano offering.

Blimey.

Not much to choose on price but there is a definite weight advantage to the Shimano unit. Is the SA just built "better"?

Still not sure I can justify spending the money but its certainly got me thinking.

Took some piccies of the rear disc adapter thing I have. Looks to me like this is intended to sit outside the dropouts, looking at the way the dropout part is offset outwards rather than inward of the disc mount point, so with the mounting point located above the stays where I would expect it to the dropout hangs outside the frame.

Or am I looking at it all wrong?

I tried placing it against a frame, slotted it onto a canti stud. It looks to sit the mount quite vertical if that makes sense, maybe the arm is intended for a larger frame / wheel although it's not a huge difference. More work required!

I think you are right rick looks totally different to my hope and I agree it looks like it should go on the outside. What you could try is (if you have a wheel, disc and caliper) is trial fit the wheel and offer up the caliper against the mount and see how it looks

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